Calculus
posted by Micah .
What is the largest rectangle that can be inscribed in the first quadrant of the ellipse 9x^2+16y^2=144?

base along xaxis, height along yaxis, bottom left vertex at (0,0).
let the top right vertex be (x,y)
from equation
y = (1/4)√(144  9x^2)
Area = xy
= x(1/4)√(144  9x^2)
differentiate using the product rule, set the derivative equal to zero and solve for x
I got x = 4√3/3 for a max area of 384√3/3
but check my arithmetic.